[mythtv-users] transcoding HD material to ease playback

lemongecko at gmail.com lemongecko at gmail.com
Fri Jan 11 21:31:33 UTC 2008

On 1/11/08, Dan Christensen <jdc at uwo.ca> wrote:
> I do have Xv.  But I would still imagine that if the source material is
> 1080p, and with my monitor being 720p, it would advantageous to
> downscale ahead of time.  Maybe it's not that important?

Ah. I thought you were going the other way, or were worried about
scaling due to aspect ratios. Then, yes, it'll make a big difference.
A 1080p frame is 2.25 times the size of a 720p frame. That's a lot
less data to decompress.

> (stuff on bitrates)
> I agree that it's not likely to be HD or memory related.  Still, the
> more data to be processed, the more cpu time I would expect it to take.

You could try. Do a nuvexport of a show twice. Once in a high bitrate,
and once in a low. See if there's much of a difference in CPU load. I
truly do not know for sure, but since you're still running the same
decoder to display the same number
resultant pixels, I don't think there will be any significant difference.

> There's no obvious pattern, except that I've noticed more problems with
> 1080p than 720p.  In general I'm not even sure how to find out stats
> about a file, e.g. codec, resolution, bitrate, interlaced/not, etc...

I find mplayer to be a simple way to go. If you start a video from a
terminal, and escape out a few seconds later, you'll have a whole host
of information that mplayer generated.

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